Vinyl cutters cut vector art, not bitmap files. Bitmap files can have lines and arcs added with a vector trace algorithm. Download InkScape at InkScape.org to be able to create vector files. I can give you a walkthrough if you like (PM me if your interested).
The 'eye' is for doing contour cutting. Contour cutting is needed to cut around pre-printed graphics. There are a couple ways this is done. One is semi-manual where there is a laser dot that you line up by eye on the registration marks. The other method is with an ARMS system that automatically reads the crop marks. This allows the cutter to register the vinyl position so it then knows where to cut on the vinyl to contour cut your images.